Well DH must think like you, he came home from his overnight run to Iowa (gee fun!), looked back there, walked over to the couch and went to sleep.
I'm guessing its not terribly urgent. What do I know.

Isn't this why you have kids?? LOL (My mum pushed me through an open louvre window when I was a kid and we went out without the backdoor key!! Cheaper than a locksmith and quicker than waiting for dad to come home from work!) Skinny arms, super flexible, likes a challenge and doing something that will gross out younger siblings?!

As to the tank cover, what about putting some flyscreen wire over the grate or some curtain netting? Both still let the air circulate but stop kamikaze fish.